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Summary of results of NASA F-15 flight research program

NASA conducted a multidisciplinary flight research program on the F-15 airplane. The program began in 1976 when two preproduction airplanes were obtained from the U.S. Air Force. Major projects involved stability and control, handling qualities, propulsion, aerodynamics, propulsion controls, and integrated propulsion-flight controls. Several government agencies and aerospace contractors were involved. In excess of 330 flights were flown, and over 85 papers and reports were published. This document describes the overall program, the projects, and the key results. The F-15 was demonstrated to be an excellent flight research vehicle, producing high-quality results.

Burcham, F. W., Jr.

Longitudinal aerodynamic and propulsion characteristics of a propulsive-wing V/STOL model at high subsonic speeds

The aerodynamic and propulsion characteristics of a 1/6-scale propulsive-wing V/STOL air-powered model was investigated over the Mach number range from 0.40 to 0.96 and at angles of attack from -5 deg to 15 deg for several fan rotational speeds. Three fanduct-exit configurations were tested, including two exit areas. The model with 25-percent-thick wing had a drag-rise Mach number of 0.85, which is typical of aircraft with thinner, conventional, unswept wings.

Salters, L. B., Jr.

Propulsion-induced aerodynamics of an ejector-configured STOVL fighter aircraft

Propulsion-induced aerodynamic effects are computed by using data obtained from tests of a full-scale model of the E-7A configuration that were run in the NASA Ames 40 x 80 and 80 x 120-foot tunnels. These effects are shown both in aerodynamic coefficients and nondimensionalized by thrust versus equivalent velocity. The test results show that the full-scale ventral nozzle-induced effects are smaller than scale model data, while the ejector-induced effects demonstrate fair agreement. The effect of tunnel test section size is primarily observed at low and static speed, high thrust conditions, as seen in comparisons of data from both tunnels. The 80 x 120-foot tunnel test gave better static thrust calibrations and permitted a greater range of test freestream velocities and angles-of-attack, extending the database provided by the full-scale model.

Poppen, William A.

MM-122: High speed civil transport

The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

Demarest, Bill

Propulsion and aerodynamic analysis of the Beta II two-stage-to-orbit vehicle

A study of a revised version of the Beta II two-stage-to-orbit vehicle has been undertaken. The goal of the study was to modify and refine critical components of the NASA/Boeing/Wright Laboratory Beta II booster design to better define a successful baseline vehicle that can provide routine access to space. The vehicle geometry was modified and corresponding aerodynamics were predicted. The propulsion system was improved by refining the nacelle design which included incorporating a variable capture area inlet, replacing the five High Speed Civil Transport derived turbine bypass turbojet engines with four variable cycle turbofan engines per nacelle, and removing the bypass duct system. The ramjet performance was adjusted for the change in airflow due to the variable capture area inlet. The second stage wing-body orbiter design was not modified for this study. The total Beta II takeoff weight which resulted was approximately 1.0 million pounds.

Davic, James R.

A Multi-Disciplinary Analysis Framework for the Design of Small Launch Vehicles

The decisions made in the conceptual design phase have large impacts on the resulting vehicle capability and cost. With the large and varied design space of Small Launch Vehicles(SLVs), it is even more important to have the data necessary to make informed design choices during the conceptual design phase. To enable extensive exploration of the SLV design space, a multi-disciplinary design framework was created. The design framework consists of trajectory, aerodynamics, propulsion, and structures disciplines. The framework then integrates and automates these tools, thus allowing for rapid design space exploration at the conceptual design phase. The outputs of the framework provide preliminary information on SLV size and structural configurations as well as propulsion and aerodynamic characteristics. Finally, the framework provides information necessary for the designer to make informed decisions on what variables lead to the desired performance characteristics and what segment of the design space would benefit from more detailed exploration.

Nikita Birbasov

Advanced Turboprop Transport Aircraft Modeling for the Electrified Powertrain Flight Demonstration Project

The objective of this study is to establish models for state of the art, representative regional non-electrified turboprop configurations in the 19 to 50 passenger capability range and assess performance impacts from advanced aircraft technologies. Two of these models will serve as reference baseline configurations for comparison to electrified aircraft propulsion (EAP) demonstrator concepts for the Electrified Powertrain Flight Demonstration (EPFD) project. The other two non-electrified configurations will primarily assess the impacts of advanced technologies on fuel consumption and CO₂ emissions. This paper details an aircraft synthesis and performance analysis approach using the General Aviation Synthesis Program (GASP) which is used to establish baseline performance capabilities, calibrate airplane and engine models using published manufacturer data and conduct technology sensitivity studies. Advanced technologies are selected from the categories of propulsion, aerodynamics, and flight systems. A GASP-Monte Carlo simulation framework for uncertainty propagation is used to obtain performance distributions of the expected fuel burn, weight reduction and CO₂ emissions reductions from advanced aircraft technologies. Significant fuel burn savings from application of aerodynamics and propulsion technologies was observed.

Dahlia D.V. Pham

Airframe-propulsion system aerodynamic interference predictions at high transonic Mach numbers including off-design engine airflow effects

The transonic speed regime for airplanes at conditions where inlet spillage takes place is discussed. A wind tunnel test program to evaluate aerodynamic performance penalties associated with propulsion system installation and operation at subsonic through low supersonic speeds was conducted. The accuracy of analytic methods for predicting transonic engine airframe interference effects was assessed. Study variables included Mach number, angle of attack, relative nacelle location, and nacelle mass flow ratio. Results include test theory comparisons of forces as well as induced pressure fields. Prediction capability of induced shock wave strength and locations is assessed. It was found that large interference forces due to engine location and flow spillage occur at transonic speeds, that theory explains these effects; and that theory can predict quantitatively these effects.

Kulfan, R. M.

Fitting aerodynamics and propulsion into the puzzle

The development of an airbreathing single-stage-to-orbit vehicle, in particular the problems of aerodynamics and propulsion integration, is examined. The boundary layer transition on constant pressure surfaces at hypersonic velocities, and the effects of noise on the transition are investigated. The importance of viscosity, real-gas effects, and drag at hypersonic speeds is discussed. A propulsion system with sufficient propulsive lift to enhance the performance of the vehicle is being developed. The difficulties of engine-airframe integration are analyzed.

Johnston, Patrick J.

Hypersonic Airbreathing Propulsion: An Aerodynamics, Aerothermodynamics, and Acoustics Competency White Paper

This White Paper examines the current state of Hypersonic Airbreathing Propulsion at the NASA Langley Research Center and the factors influencing this area of work and its personnel. Using this knowledge, the paper explores beyond the present day and suggests future directions and strategies for the field. Broad views are first taken regarding potential missions and applications of hypersonic propulsion. Then, candidate propulsion systems that may be applicable to these missions are suggested and discussed. Design tools and experimental techniques for developing these propulsion systems are then described, and approaches for applying them in the design process are considered. In each case, current strategies are reviewed and future approaches that may improve the techniques are considered. Finally, the paper concentrates on the needs to be addressed in each of these areas to take advantage of the opportunities that lay ahead for both the NASA Langley Research Center and the Aerodynamic Aerothermodynamic, and Aeroacoustics Competency. Recommendations are then provided so that the goals set forth in the paper may be achieved.

Drummond, J. Philip

Advanced Turboprop Transport Aircraft Modeling for the Electrified Powertrain Flight Demonstration Project

The objective of this study is to establish models for state of the art, representative regional non-electrified turboprop configurations in the 19-50 passenger capability range and assess performance impacts from advanced aircraft technologies. Two of these models will serve as reference baseline configurations for comparison to electrified aircraft propulsion (EAP) demonstrator concepts for the Electrified Powertrain Flight Demonstration (EPFD) project. The other two non-electrified configurations will primarily assess the impacts of advanced technologies on fuel consumption and CO₂ emissions. This paper details an aircraft synthesis and performance analysis approach using the General Aviation Synthesis Program (GASP) which is used to establish baseline performance capabilities, calibrate airplane and engine models using published manufacturer data and conduct technology sensitivity studies. Advanced technologies are selected from the categories of propulsion, aerodynamics, and flight systems. Performance assessments use Monte Carlo method coupled with GASP simulations to obtain performance distributions of the expected fuel burn, propulsive, aerodynamic, and weight benefits on the representative turboprop configurations from the application of advanced technologies. The final paper will present the impact of the advanced technologies on fuel burn and CO₂ emissions.

aircraft performance

Computational Investigation of Powered Descent for Human-Scale Mars Landers

NASA human-scale Mars entry, descent, and landing vehicles currently under consideration have system requirements beyond the current state of the art. Specifically, heritage approaches for deceleration using parachutes and initiating engines at subsonic speeds are not adequate to land these large vehicles (50-60 metric ton entry mass) precisely (within 50 meters of a surface target). Therefore, the present approach for landing humans on Mars utilizes entry vehicles with large aerodynamic surface areas that transition to the descent and landing phase by initiating retropropulsion at supersonic speeds. Vehicle performance, including stability and control, depends on accurate characterization of the aerodynamic-propulsive interference effects, especially at engine initiation, when the vehicles are transitioning from an entry attitude to that suitable for descent and landing. This paper summarizes the human Mars entry vehicle configurations, retropropulsion integration, performance assumptions, and expected flight environment at engine initiation. Cases spanning supersonic, transonic, and subsonic conditions during powered descent are analyzed using four computational fluid dynamics codes, all of which have been previously applied to supersonic retropropulsion at varying scales and conditions. The results of the analysis are used to develop an aerodynamic-propulsive interference model that has since been applied in trajectory simulations to augment the fidelity of human-scale Mars entry vehicle performance.

Ashley M Korzun

Overview of NASA's Integrated Design and Engineering Analysis (IDEA)Environment

Historically, the design of subsonic and supersonic aircraft has been divided into separate technical disciplines (such as propulsion, aerodynamics and structures) each of which performs their design and analysis in relative isolation from others. This is possible in most cases either because the amount of interdisciplinary coupling is minimal or because the interactions can be treated as linear. The design of hypersonic airbreathing vehicles, like NASA s X-43, is quite the opposite. Such systems are dominated by strong non-linear interactions between disciplines. The design of these systems demands that a multi-disciplinary approach be taken. Furthermore, increased analytical fidelity at the conceptual design phase is highly desirable as many of the non-linearities are not captured by lower fidelity tools. Only when these systems are designed from a true multi-disciplinary perspective can the real performance benefits be achieved and complete vehicle systems be fielded. Toward this end, the Vehicle Analysis Branch at NASA Langley Research Center has been developing the Integrated Design & Engineering Analysis (IDEA) Environment. IDEA is a collaborative environment for parametrically modeling conceptual and preliminary launch vehicle configurations using the Adaptive Modeling Language (AML) as the underlying framework. The environment integrates geometry, configuration, propulsion, aerodynamics, aerothermodynamics, trajectory, closure and structural analysis into a generative, parametric, unified computational model where data is shared seamlessly between the different disciplines. Plans are also in place to incorporate life cycle analysis tools into the environment which will estimate vehicle operability, reliability and cost. IDEA is currently being funded by NASA s Hypersonics Project, a part of the Fundamental Aeronautics Program within the Aeronautics Research Mission Directorate. The environment is currently focused around a two-stage-to-orbit configuration with a turbine based combined cycle (TBCC) first stage and reusable rocket second stage. This paper provides an overview of the development of the IDEA environment, a description of the current status and detail of future plans.

Robinson, Jeffrey S.

The effects on propulsion-induced aerodynamic forces of vectoring a partial-span rectangular jet at Mach numbers from 0.40 to 1.20

An investigation was conducted in the Langley 16-foot transonic tunnel to determine the induced lift characteristics of a vectored thrust concept in which a rectangular jet exhaust nozzle was located in the fuselage at the wing trailing edge. The effects of nozzle deflection angles of 0 deg to 45 deg were studied at Mach numbers from 0.4 to 1.2, at angles of attack up to 14 deg, and with thrust coefficients up to 0.35. Separate force balances were used to determine total aerodynamic and thrust forces as well as thrust forces which allowed a direct measurement of jet turning angle at forward speeds. Wing pressure loading and flow characteristics using oil flow techniques were also studied.

Capone, F. J.

Effects of nozzle exit location and shape propulsion-induced aerodynamic characteristics due to vectoring twin nozzles at Mach numbers from 0.40 to 1.2

An investigation was conducted in the Langley 16-foot transonic tunnel to determine the induced lift characteristics of a vectored-thrust concept in which jet-exhaust nozzles were located in the fuselage at or near the wing trailing edge. The effects of moving twin rectangular nozzles rearward from the wing trailing edge and of round nozzles at the trailing edge only were studied at Mach numbers from 0.4 to 1.2, angles of attack up to 14 deg, and thrust coefficients up to 0.35. Nozzle deflection angle varied from 0 deg to 45 deg. Separate force balances were used to determine both total aerodynamic and thrust forces and thrust forces alone which allowed for a direct measurement of jet turning angle at forward speeds. The Reynolds number per meter varied from 8.20 x 1 million to 13.12 x 1 million.

Capone, F. J.